Our major impact was in the description of GH-neurosecretory dysfunction in a subgroup of short-statured children. This appears to be a sound explanation why certain non-GH deficient children respond to exogenous hGH. Our data suggests that these children have an abnormality in the neurosecretion of GH resulting in a decreased GH output. This observation is an outgrowth of our studies in irradiated children and monkeys. Additional studies draw into question some of the traditional methods and interpretation of GH provocative tests in GH deficiency. Our studies demonstrate that classical provocative testing may give misleading results as to the total output of GH. In addition, biosynthetic hGH will significantly increase linear growth velocity in GH deficient children. Our laboratory has continued to utilize the non-human primate model to investigate the neuroregulation of GH secretion as well as the mechanisms controlling the onset of puberty in the male. With lesioning studies, we have successfully shown that the arcuate nucleus is important both in the regulation of GH and gonadotropin secretion in the male. In another series of experiments, we have uncovered a short 11-15 minute ultradian rhythm in gonadotropin pulsing. In addition, using a newly synthesized potent GnRH antagonist, we have demonstrated rapid effect and dose-responses in intact male animals. One further study has demonstrated a paradoxical effect, in animals pre-treated with a dopamine hydroxylase inhibitor, of increase doses of human pancreatic tumor growth factor on GH release.